FER/Drop - a CFD (Computational Fluid Dynamics) program for the simulation of
droplet spreading and heat transfer during thermal spray
FER/Drop is a
special finite element program devoted to the simulation of fluid dynamics
problem coupled with heat transfer phenomena. The mathematical frame is based on
the laws of conservation of mass, momentum, and energy. The differential
equations (Navier-Stokes) are discretized by the Lagrangian finite element
method. A remeshing technique is used to treat the large deformation of free
surfaces during the flattening process of molten droplets. The Newton Raphson
method is used to solve the non linear equation and the solution of transient
system is obtained by means of an implicit Euler method. The effect of the
substrate roughness is taken into account by introducing the friction resistance
at the particle-substrate interface. The transient flattening behaviour of a
fully molten liquid aluminium particle impinging onto a rough surface has been
investigated numerically by means of the program.
The
numerical results show that the spreading process of a liquid particle is
governed not only by the inertia and viscous forces but also by the frictional
resistance of the substrate surface. The roughness has hence a significant
influence on the spreading velocity, flattening degree, flattening time, as well
as splat size and shape.
Architecture of the program FER/Drop
The 3D view of the spreading procedure of a molten particle during plasma
spray
Iso-value of the velocity fields during the flattening of a molten
particle
The remeshing method for modelling the large deformation of the
particle
The influence of substrate roughness on the flattening of the molten
particle
Evolution of temperature during the flattening process
The
following animation images show the variation of temperature and radial velocity
of a molten droplet impacting the substrate.
